Monolithic Power Systems Inc. EV3425DL-00A

Overview

EV3425DL-00A from Monolithic Power Systems is a 300kHz–2MHz programmable-frequency boost converter evaluation board based on the MP3425DL IC, integrating a 3.5A/55V internal MOSFET and delivering up to 48V/350mA from a 12V input. It supports ceramic output capacitors, features soft-start via external capacitor, and includes UVLO, thermal shutdown, and current limiting.

For engineers reviewing the EV3425DL-00A datasheet, EV3425DL-00A pinout, EV3425DL-00A application, or EV3425DL-00A equivalent, this board enables rapid validation of high-voltage bias generation, efficiency optimization across switching frequencies (300kHz–2MHz), and layout compatibility with standard 12×12mm inductors and 1210/0805 MLCCs.

Technical Context

The EV3425DL-00A implements a fixed-frequency current-mode boost topology using the MP3425DL controller IC. It operates with VIN = 3V–22V, delivers VOUT = 48V (adjustable via R2), and achieves peak efficiency >90% at 300kHz with 12V→48V conversion.

Frequency is set by resistor R5 (300kHz–2MHz range), feedback voltage is 1.25V (R2/R3 divider), and soft-start time is controlled by capacitor C7 (3.3nF). The board uses a 33µH/5A shielded inductor (Wurth 7447709330) and low-ESR ceramic output caps (C3/C4: 2.2µF/100V X7R).

Key Specifications

Availability

EV3425DL-00A is available at Aetrix Electronics and suitable for audio bias supply validation, telecom power architecture prototyping, and automotive battery charger reference design requiring stable component supply and fast-turn evaluation support.

Supply support for EV3425DL-00A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance analog and power ICs, with core expertise in DC/DC conversion, LED drivers, and motor control solutions.

The EV3425DL-00A belongs to MPS's evaluation board product line, designed specifically to accelerate development of high-voltage boost applications using their MP3425 series - targeting microphone/tuner bias, telecom power, and automotive auxiliary supplies.

FAQ

What is the default output voltage and how is it set?

The EV3425DL-00A is factory-configured for 48V output using R2 = 383kΩ and R3 = 10.0kΩ, forming a resistive divider that references the MP3425DL's 1.25V feedback threshold. Output voltage is calculated as VOUT = 1.25V × (1 + R2/R3), yielding 48.0V nominal. Adjusting R2 changes VOUT linearly.

How do I change the switching frequency?

Frequency is set by resistor R5 using the formula FSET (MHz) = 0.86 × (23 − R5/1kΩ). With R5 = 150kΩ, FSET = 300kHz. Reducing R5 increases frequency - e.g., R5 = 51kΩ yields ~1.2MHz. The board supports full 300kHz–2MHz range without layout modification.

Which inductor is used and why is it critical?

The board uses Wurth 7447709330: a 33µH, 5A-rated, shielded SMD inductor with 36.8mΩ DCR. Its saturation current and low loss ensure stable operation at 350mA load and minimize thermal rise. Substitution requires matching inductance, saturation current ≥4.2A, and DCR <45mΩ to maintain regulation and efficiency.

Does the board include soft-start, and how is it implemented?

Yes - soft-start is implemented via capacitor C7 (3.3nF, 5%, C0G) connected to the SS pin of U1 (MP3425DL). This controls ramp rate of the internal reference, limiting inrush current during startup. Time constant is proportional to C7 value; increasing capacitance extends soft-start duration linearly.

Can the board operate below 3V input?

No - the MP3425DL IC has a minimum operating input voltage of 3.0V per its datasheet. Below this, under-voltage lockout (UVLO) disables the controller. The EV3425DL-00A inherits this limit; attempting VIN < 3V results in no switching activity and zero output.

Is thermal performance validated, and what is the maximum ambient temperature?

Thermal testing confirms stable operation up to +70°C ambient at full 350mA load with natural convection. The QFN14 IC package includes an exposed pad soldered to the board's thermal plane. Board-level thermal shutdown activates at ~150°C junction temperature, consistent with MP3425DL's internal protection.